Oestrogen: function, normal levels, and imbalances

Find out answers to common questions about this important reproductive hormone.

Oestrogen is a key player when it comes to reproductive health, for both men and women. But did you know it also contributes to mood, bone density, and heart health? 

We look at the types of oestrogen, what your levels should be, and what happens if your levels fall out of balance. 


What is oestrogen?

Oestrogen is a key steroid hormone that plays a key role in reproductive health.

The three main types of oestrogen are: 

  • Oestrone (E1) – this oestrogen is mostly made during and after menopause. It’s made by the adrenal glands and fat tissues. 
  • Oestradiol (E2) – this is the most common type of oestrogen in women before menopause. It’s made by the ovaries and is crucial for reproductive and sexual function. This is the type we test for in most of our blood tests.
  • Oestriol (E3) – this is the weakest form of oestrogen and is present in significant amounts only during pregnancy. It’s made by the placenta and plays an important role in the development of the foetus. 

The different forms of oestrogen work together to regulate various processes in the body.


What does oestrogen do?

Oestrogen plays many different roles in both men and women. 

In women, oestrogen: 

  • Regulates the menstrual cycle
  • Prepares the womb for pregnancy
  • Is responsible for the development of female sexual characteristics
  • Maintains healthy skin and hair
  • Regulates cholesterol levels and protects heart health

In men, oestrogen: 

  • Supports sperm production
  • Plays a role in balancing the effects of testosterone

In both men and women, oestrogen: 

  • Contributes to sex drive (libido)
  • Maintains bone density
  • Influences mood and emotional wellbeing


What is a normal oestrogen level?

A normal level of oestrogen for men is relatively fixed. However, for women, normal levels will depend on whether she is pre- or postmenopausal, the stage of the menstrual cycle, and whether she is pregnant. During perimenopause, oestrogen levels are often erratic and can swing from very low to very high. 

The table below is given as a guide only and will vary between labs. 


Normal oestradiol level







114–332 (follicular)

222–1,959 (ovulation)

222–854 (luteal)

<18.4–505 (postmenopausal)

31–90 (follicular)

60–534 (ovulation)

60–233 (luteal)

<5–138 (postmenopausal)


563–11,902 (1st trimester)

5,729–79,098 (2nd trimester)

31,287–110,100 (3rd trimester)

153–3,242 (1st trimester)

1,560–21,545 (2nd trimester)

8,522–29,989 (3rd trimester)

Not that sub-phases throughout the menstrual cycle can affect your result. For example, a sample taken during the late follicular phase will likely be much higher than a sample taken during the early follicular phase.


Symptoms of an oestrogen imbalance

It’s normal for a woman’s oestrogen levels to naturally fluctuate throughout the menstrual cycle. But if oestrogen levels remain consistently low or high, it can lead to symptoms. 

Symptoms of raised oestrogen include:

  • Irregular or heavy periods
  • Breast tenderness
  • Irritability and mood swings
  • Headaches
  • Sleep disturbances
  • Decreased sex drive

In men, high levels of oestrogen may cause fertility problems, gynaecomastia (man boobs), and erectile dysfunction.


Symptoms of low oestrogen include: 

  • Hot flushes or night sweats
  • Sleep disturbances
  • Missed periods
  • Weight gain
  • Difficulty concentrating
  • Irritability and mood swings
  • Painful sex due to vaginal dryness
  • Dry, thin, or itchy skin
  • Reduced sex drive
  • Headaches
  • Fractures (low oestrogen levels can lead to thinner bones or osteoporosis)


What causes low oestrogen levels?

Low oestrogen naturally declines with age and through menopause, but there are also certain conditions and other factors that can cause levels to drop. 

Causes of low oestrogen include:

  • Overexercising – regular gentle exercise can help support the body’s natural hormone balance and help control excess oestrogen levels (which incidentally reduces the risk of breast cancer). However, too much vigorous exercise may cause levels to fall below the normal range.
  • Eating disorders – conditions like anorexia and bulimia deprive the body of nutrients it needs to maintain a healthy hormone balance.
  • Stress –stress has a significant effect on all hormones. During the menstrual cycle, it can aggravate natural falls in oestrogen [1].
  • Surgical removal of the ovaries – some women have their ovaries removed (oophorectomy) as part of their treatment. Since oestrogen is predominantly made in the ovaries, women are usually offered oestrogen to restore natural levels (HRT). 
  • Premature ovarian insufficiency (POI) – POI is a condition where the ovaries stop producing eggs before the age of 40.
  • Pituitary conditions – the pituitary gland produces luteinising hormone (LH) and follicle-stimulating hormone (FSH) which impact oestrogen production and release. 


What causes high oestrogen levels?

High oestrogen levels are usually due to one of three reasons: your body is making too much, you’re getting too much from medications, or your body isn’t breaking down oestrogen as it should. 

Causes of high oestrogen include:

  • Medications – HRT may cause oestrogen levels to overshoot at first, and it may take some time to adjust to the right dose. Hormonal contraception may also lead to increased oestrogen levels. 
  • Being overweight – fat cells produce oestrogen and also contain an enzyme that converts androgens (male hormones) to oestrogen. 
  • Alcohol – alcohol can impair the metabolism of oestrogen in the liver. It also increases the activity of aromatase, an enzyme that converts male hormones to oestrogen. 
  • Liver disease – for the same reasons above, liver disease can also lead to raised oestrogen levels.
  • Stress – stress has a variety of effects on the hormone system. It may lead to weight gain (which increases oestrogen) or reduce progesterone levels, which help to balance the effects of oestrogen. 
  • Ovarian tumours – some ovarian tumours release oestrogen. 


What is oestrogen dominance?

Oestrogen dominance is a term that describes a high oestrogen level relative to progesterone. This can occur due to absolute increases in oestrogen levels, a decline in progesterone, or a combination of both.

This term is more commonly used in alternative medicine. In mainstream medicine, the focus is typically on diagnosing and treating specific hormonal imbalances and conditions rather than referring to “oestrogen dominance”. 

Having too much oestrogen can affect both men and women, but it’s more common in women. 

Symptoms of oestrogen dominance may include: 

  • Abnormal periods
  • Mood swings
  • Weight gain
  • Fatigue
  • Breast tenderness
  • Headaches or migraines
  • Sleep disturbance

These symptoms are especially common during perimenopause. Oestrogen levels fluctuate significantly and begin to decline, while progesterone levels tend to decline more quickly. This can give rise to an imbalance, which some people refer to as oestrogen dominance. 

Too much oestrogen can also stimulate the growth of fibroids in the womb and, in some cases, exacerbate endometriosis. Endometriosis is a condition where tissue similar to the lining of the womb grows in other places. Having high levels of oestrogen can also increase the risk of conditions like breast and ovarian cancer. 


How to lower oestrogen levels naturally

If your oestrogen levels are raised, several lifestyle changes may help to normalise your levels. 

Natural ways to reduce your oestrogen levels include:

  • Losing weight if you’re overweight
  • Reducing your alcohol intake [2]
  • Following a healthy diet – the Mediterranean diet has been shown to be effective [3]
  • Reducing your intake of red meat and dairy foods [4,5]

If your levels remain persistently low or you have ongoing symptoms, it’s best to speak to your doctor to investigate any possible underlying causes.


How to increase oestrogen levels naturally

Firstly, it’s important to establish why oestrogen levels are low and treat any underlying conditions. 

Often low oestrogen levels are associated with perimenopause or menopause, in which case, hormone replacement therapy (HRT) is often very effective at managing some of the associated symptoms, like hot flushes, mood swings, and low libido. 

Find out more about managing the symptoms of menopause.

Before trying hormone therapies, lifestyle changes are often recommended in the first instance. Things like quitting smoking and making sure you’re not overexercising or underweight may help to increase your oestrogen levels. 


How to check your oestrogen levels from home

You can check your oestrogen levels from home with our Female Hormone Blood Test or Male Hormone Blood Test. These tests also check your levels of other important hormones such as LH, FSH, and testosterone.

When you take your test, it’s helpful to let us know in the supporting information if you are taking any of the following:

  • Antibiotics (such as ampicillin or tetracycline)
  • Corticosteroids
  • DHEA supplements
  • Oestrogen-containing medications
  • Medicines for mental health conditions (such as phenothiazine)
  • Testosterone
  • Over-the-counter or herbal preparations

Each of these medications may affect your levels of oestrogen.



  1. Role of Sex Hormone Levels and Psychological Stress in the Pathogenesis of Autoimmune Diseases - PMC. [cited 8 Feb 2024]. Available: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5498122/
  2. Rachdaoui N, Sarkar DK. Effects of Alcohol on the Endocrine System. Endocrinol Metab Clin North Am. 2013;42: 593–615. doi:10.1016/j.ecl.2013.05.008
  3. Carruba G, Granata OM, Pala V, Campisi I, Agostara B, Cusimano R, et al. A traditional Mediterranean diet decreases endogenous estrogens in healthy postmenopausal women. Nutr Cancer. 2006;56: 253–259. doi:10.1207/s15327914nc5602_18
  4. Sánchez-Zamorano LM, Flores-Luna L, Angeles-Llerenas A, Ortega-Olvera C, Lazcano-Ponce E, Romieu I, et al. The Western dietary pattern is associated with increased serum concentrations of free estradiol in postmenopausal women: implications for breast cancer prevention. Nutr Res. 2016;36: 845–854. doi:10.1016/j.nutres.2016.04.008
  5. Brinkman MT, Baglietto L, Krishnan K, English DR, Severi G, Morris HA, et al. Consumption of animal products, their nutrient components and postmenopausal circulating steroid hormone concentrations. Eur J Clin Nutr. 2010;64: 176–183. doi:10.1038/ejcn.2009.129